This invention relates generally to inflatable modules or vessels. In particular, this invention relates to such a module that is lightweight, collapsible and compact prior to deployment, and is capable of being subsequently inflated to provide a relatively large volume for storage, containment, human habitation, shelter, or work, as well as for space flight. This invention also relates to an inflatable module or vessel that may be highly loaded. The benefits of this invention include a vessel having a high strength-to-weight ratio, a minimum volume prior to inflation, high-pressure and/or large volume capability, ease of manufacturing and thus low cost, and an inflated vessel with a relatively low leak rate.
In general, modules for use in one location can either (1) be assembled at another location and transported to the location of use or (2) be assembled at the use location with their individual parts being transported from other locations. Each method of assembly has advantages and drawbacks. For example, if a module is to be assembled on earth and thereafter transported into orbit, then the overall size of the module becomes a limiting factor.
Pre-assembled modules, however, do provide certain advantages. For instance, all of the components and system interfaces of a pre-assembled module may be tested, calibrated, and repaired at the manufacturing location where replacement parts and technical expertise are readily available. In addition, a pre-assembled module can be utilized almost immediately once at its use location without having to wait for assembly or testing time.
Like pre-assembled modules, modules assembled on the use site also provide certain advantages. For example, the size and weight of an orbit-assembled module is theoretically unlimited, thereby providing designers with a greater range of design parameters and possibilities.
It would thus be advantageous over the prior art to provide inflatable modules that combine the advantages offered by, and limit some of the drawbacks inherent in, both pre-assembled and site assembled modules.
Space modules are generally known to the prior art. Illustrative of such modules are U.S. Pat. No. 3,169,725 issued to Berglund on Feb. 16, 1965; U.S. Pat. No. 3,144,219 issued to Schnitzer on Aug. 11, 1964; U.S. Pat. No. 4,730,797 issued to Minovitch on Mar. 15, 1988; U.S. Pat. No. 4,792,108 issued to Bull on Dec. 20, 1988; U.S. Pat. No. 4,825,599 issued to Swann, Jr. on May 2, 1989; U.S. Pat. No. 5,350,138 issued to Culbertson et al. on Sep. 27, 1994; U.S. Pat. No. 5,429,851 issued to Sallee on Jul. 4, 1995; and U.S. Pat. No. 5,580,013 issued to Velke on Dec. 3, 1996.
Although most of the listed patents include ingenious structures to be utilized in the outer space environment and some even include expandable components, none of the inventions disclosed in such patents include a structure that is compact during the transport or deployment stage and can thereafter be inflated to provide a fully usable space in the deployed stage.
Accordingly, the objectives of this invention are to provide, inter alia, a module that:
combines the advantages offered by, and limits the drawbacks inherent in, pressembled assembled and in situ assembled modules;
is lightweight, collapsible and compact prior to and during its transport or pre-deployment stage;
is capable of being subsequently inflated while in its deployed stage to provide a relatively larger volume for storage, containment, human habitation, shelter, or work, as well as for space flight;
minimizes the number of parts to be assembled as well as the amount of work necessary to complete the assembly;
for space-flight, may be launched in existing launch vehicles;
allows for the majority of its components and system interfaces to be tested and calibrated prior to transport and deployment;
for space flight, may be efficiently and easily converted from its structurally efficient launch configuration to its deployed configuration;
is inflatable from its launch or transport configuration to its deployed configuration, thereby providing a relatively larger useable volume; and
utilizes a number of key components for multiple functions, thereby providing mass and volume efficiency to the module.
Other objectives of the invention will become apparent from time to time throughout the specification and claims as hereinafter related.
To achieve such objectives, the invention includes a module that generally comprises a structural core and an inflatable shell. The inflatable shell is searingly attached to the structural core. In its pre-deployment or launch configuration, the interior and thickness of the inflatable shell may be collapsed by vacuum. Also in this configuration, the inflatable shell may be efficiently folded around the structural core, and for space flight, the module may be loaded into the payload bay of an existing launch vehicle, such as the Space Shuttle. On location, in orbit for example, the module is deployed, the inflatable shell is inflated, and the module achieves its deployed configuration. In its deployed configuration, the thickness of the inflatable shell automatically expands from its collapsed state to its full thickness, and the inflatable shell is inflated around the structural core, defining therein a large volume useable, for example, as habitable space for astronauts. A plurality of removable shelves may be arranged interior to the structural core in the pre-deployment or launch configuration. The structural core may also include at least one longeron that, in conjunction with the shelves, primarily constitute the rigid, strong, and lightweight load-bearing structure of the module during transport or launch. The removable shelves are detachable from their arrangement in the transport or launch configuration so that, when the module is in its deployed configuration and transport or launch loads no longer exist, the shelves may be rearranged to provide a module interior arrangement suitable for example, for human habitation and work. In the preferred embodiment, to provide efficiency in structural load paths and attachments, the shape of the inflatable shell is a cylinder with semi-toroidal ends in its deployed configuration.
In a preferred embodiment, the inflatable shell of the module consists of four primary components: the inner liner, bladder, restraint layer and seal interface. Alternate embodiments may not have an inner liner or seal interface, but will most likely still have a structural restraint layer and bladder. In some cases, the bladder and restraint layer may be incorporated as one unit.
The module according to the present invention may include a flexible restraint layer that is capable of taking a large load, and this feature is incorporated in the preferred design. The module may transition from a flexible restraint layer to a rigid structure to allow for airlocks, entry hatches, windows, or inflation monitoring ports. Especially for space applications but also for other applications, the inflated module has a relatively low leak rate.
Further objectives of this invention are to provide, inter alia, an inflatable highly loaded pressure vessel that:
is lightweight (when compared to conventional pressure vessels of equal size and pressure capability;
is capable of carrying a large load due to high pressure and/or large volume;
may be efficiently packaged prior to deployment/inflation;
due to its lower weight is easier to transport prior to inflation;
is capable of being inflated at its desired locations;
minimizes assembly time and parts;
is easy to manufacture by reducing the part count and assembly time (when compared to conventional pressure vessels of equal size and pressure capability);
is relatively low cost due to the ease in manufacturing; and
has a low permeability rate; and is capable of incorporating an interface between the flexible bladder and load bearing restraint layer and a rigid structural interface such as an airlock, entry hatch, window, and inflation/monitoring ports.
Assorted uses for the inflatable module include a large habitation/storage module for terrestrial, space, or other harsh environment applications, a hyperbolic chamber/airlock, a ballast for ocean fairing vessels, a life boat-type vessel, and a flexible pressure tank.
It is also an object of the invention to provide an inflatable module including one or more rigid structural pass through frames and an inflatable shell. The shell has a pre-deployment configuration in which the shell is collapsed and deflated, and a deployed configuration in which the shell is inflated and defines an interior space. The inflatable shell includes a flexible restraint layer preferably comprising interwoven elongate longitudinal straps and hoop straps. The flexible restraint layer is structurally secured to each of the one or more rigid structural pass through frames, and a bladder is searingly and separately attached to the pass through frames. Longitudinal straps and hoop straps may be connected at selectively spaced intervals by a stitch or other fastening device. Another type of stitch may be used to connect a longitudinal strap with either an end of the same strap or with another longitudinal strap. The spacing between successive rows of the stitch may be varied to increase the strength of the stitch. Two adjacent longitudinal straps may form a single loop which is attached to the longitudinally spaced ends of a structural core of the module. Each end of the single loop preferably is wrapped around a roller secured to the structural core. The bladder may comprise one or more bladder layers. If two or more bladder layers are provided, the bladder layers may be connected by selectively spaced fastening patches that would fail prior to damaging the bladder layers. The bladder or outermost bladder layer may be intermittently secured to the restraint layer by other fastening patches.
Another object of the invention is to provide an inflatable module with a structural core and inflatable shell, in combination with an improved deployment system for releasing the shell from a pre-deployment configuration in which the shell is collapsed, deflated, and folded around the structural core, to a deployed configuration in which the shell is inflated and surrounds the structural core to define an enclosed space interior of the shell. The deployment system may utilize multiple cords or other flexible deployment members to connect two adjacent gores when the shell is folded around the structural core, and allows deployment to be achieved by cutting one cord in a chain of multiple cords which connect the two adjacent gores. In another embodiment, circumferentially spaced cords may form another chain which surrounds the collapsed and deflated shell, and cutting one of the circumferential cords releases each of the cords in the circumferential chain, which in turn releases each of multiple cords which connect adjacent gores.
Still another object of the invention is to provide improvements to an inflatable shell of a module comprising a plurality of circumferentially spaced gores, wherein each of a plurality of layers within the shell are spaced from other layers by flexible cables each having a plurality of stops along the length of the cable for positioning the spaced apart layers when the shell is inflated. Each of the plurality of layers may comprise layer segments which overlap a respective cord. Foam layers may be spaced between two spaced apart layers, with the foam in each layer positioned within a bag spaced in one of the plurality of gores. A vacuum in each bag may reduce the spacing between layers when the shell is collapsed and deflated.
When the module of the present invention is intended for space applications, the inflatable shell may be provided with an atomic oxygen resistant layer which is spaced from the insulation layer by a deployment layer. The bladder may then be spaced opposite the deployment layer with respect to the insulation layer. A plurality of deployment tabs each secured to the deployment layer may extend through the atomic oxygen resistant layer for maintaining the shell in the pre-deployment configuration and for selectively releasing the shell to the deployment configuration.
These and further objects, features, and advantages of the present invention will become apparent from the following detailed description, wherein reference is made to the figures in the accompanying drawings.